PSI - Issue 44

Rebecca Fugger et al. / Procedia Structural Integrity 44 (2023) 2166–2173 Author name / Structural Integrity Procedia 00 (2022) 000–000

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Fig. 4. Shear stress-strain response curves of (a) bare textile; (b) mortar matrix; (c) cement-based composites and (d) lime-based composites

Response curves of T9 and T15 specimens start with an apparent increase in shear stiffness, probably due to the imperfect alignment of the textile. Thereafter, the curves display an elastic-linear behaviour (average G equal to 0.28 kN/mm 2 and 0.43 kN/mm 2 for T9 and T15 respectively) until reaching the peak loads, that are 71.7 N/mm 2 for T9 and 88.0 N/mm 2 for T15. By this time, the yarns had gradually started to break in the internal part of the grip area. The same accentuated trend also occurs in mortar specimens, probably related to the imperfect mortar-frame contact at the start of the test. Exceeded this value, the mortar specimens have a constant shear modulus (2.61 kN/mm 2 for M-C and 2.23 kN/mm 2 for M-L), after which failure occurs at an average shear stress of 6.6 N/mm 2 and 2.4 N/mm 2 for M-C and M-L, respectively, followed by a loss of strength due to the increase in stresses at the corners. Moreover, composite specimens, exhibited an ascending elastic branch from the beginning, until the creation of a first horizontal crack in one of the external mortar layers. The average values of shear stiffness are 2.64kN/mm 2 for T9-C, 2.31 kN/mm 2 for T15-C, 2.09kN/mm 2 for T9-L and 2.77 kN/mm 2 for T15-L. Failure occurred by the progressive creation of horizontal cracks until the shear strength, whose average value are 7.0 N/mm 2 and 8.6 N/mm 2 for T9-C and T15-C respectively,